Field of the Invention
The present invention relates to a process for producing a hollow optical fiber and a device for producing an optical fiber using this process.
More particularly, the invention relates to embodiments of specific optical fibers intended for special applications in the area of optical fiber sensors.
These optical fibers make it possible to convey optical data according to the usual mode of operation of monomode optical fibers and they have an inner structure which promotes their sensitivity to such physical quantities as the pressure, the voltage and the electric field.
In a general manner and according to the invention, the optical fiber exhibits an anisotropic inner structure.
On both sides of the guide core, two recesses are made according to a production method of the present invention.
According to a first embodiment, the optical fiber with a hollow structure (FASE: fibre optique a structure evidee) is used as an intrinsic pressure sensor. In such a sensor, the fiber should exhibit a homogeneous structure over a great length (several hundred meters).
The invention describes a particular embodiment and a control method necessary for obtaining great lengths of homogeneous fiber.
According to a second embodiment, a method for obtaining optical fibers with conductive channels is described.
In the two recesses of the FASE fiber, there are placed conductive elements such as metal wires, which are inserted in the fiber during the fiber drawing operation according to a suitable variant, according to the invention, relative to the method known to one skilled in the art.
This type of optical fiber can be used for many applications, in particular in the area of optical fiber and/or integrated optical sensors. By way of a nonlimiting example, such a structure can be advantageously used to take advantage of the properties of the Kerr effect. It is known by one skilled in the art that an optical fiber of great length can be packaged in a small space, which, combined with the slight attenuation of the light signal, makes it possible to amplify cumulatively the effect over a great length, a slight effect or a low transducer coefficient.